shop detail drawing review and approval guidelines

8/18/2019 Shop Detail Drawing Review and Approval Guidelines

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AASHTO/NSBA Steel Bridge Collaboration

G 1.1 - 2000

Shop Detail Drawing Review/Approval Guidelines

AASHTO/NSBA Steel Bridge Collaboration


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AASHTO / NSBA Steel Bridge Collaboration

Task Group 1, Detailing

Walter Gatti, Tensor Engineering, Chair

Fred Beckmann National Steel Bridge Alliance

George Crosland High Steel Structures

Denis Dubois Maine Department of Transportation

Jon Edwards Illinois Department of Transportation

Dennis Golabek URS Corporation

Bob Kase High Steel Structures

Al Laffoon Missouri Department of Transportation - RetiredDon Lee High Steel Structures

Vasant Mistry Federal Highway Administration

Dennis Noernberg AFCO Steel

Paul Rimmer New York Department of Transportation

Larry Roberts Louis Berger Group

Gary Wisch DeLong’s, Inc.

John Yadlosky HDR Engineering

i Copyright © 2000 by the AASHTO/NSBA Steel Bridge Collaboration.All rights reserved.


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Table of Contents

Section 1: Definitions ..................................................................................................................... 1

1.1 Contract.............................................................................................................................. 1

1.2 Shop Detail Drawings........................................................................................................ 11.3 Fabricator........................................................................................................................... 1

1.4 Owner ................................................................................................................................ 1

1.5 Contractor .......................................................................................................................... 11.6 Approval ............................................................................................................................ 1

1.7 Principal Controlling Dimensions, Material and Connection Properties .......................... 2

1.8 Construction Change ......................................................................................................... 2

Section 2: Responsibilities.............................................................................................................. 3 2.1 Fabricator........................................................................................................................... 3

2.2 Owner ................................................................................................................................ 3

2.3 Team Effort........................................................................................................................ 32.4 Professional Seal................................................................................................................ 4

Section 3: General Review Guidelines ........................................................................................... 5

3.1 Materials ............................................................................................................................ 5

3.2 Weld Symbols.................................................................................................................... 53.3 Format................................................................................................................................ 5

3.4 Submittal Procedures ......................................................................................................... 5

3.5 Number of Drawing Copies............................................................................................... 53.6 Reduced-Size Copies ......................................................................................................... 6

3.7 Accuracy ............................................................................................................................ 6

3.8 Drawings Not Required ..................................................................................................... 6

Section 4: Approval Checklist ........................................................................................................ 7

4.1 Principal Controlling Dimensions, Material and Connection Properties .......................... 7

4.2 Web and flange plates of welded members and rolled beam stringers.............................. 7

4.3 Stiffener and connection plates.......................................................................................... 7

4.4 Bolted Splices .................................................................................................................... 74.5 Crossframes and diaphragms............................................................................................. 7

4.6 Camber and/or mid-ordinate for cambered rolled beams or girder sections (spot

check)................................................................................................................................. 84.7 Elevation at center of span or segment, field-splice, abutment and pier ordinates

on shop assembly diagrams ............................................................................................... 8

4.8 Number and spacing of bolts in floor beam and cross girder connections as well

as special attachments (brackets, pot bearings, etc.) ......................................................... 84.9 General notes and detail sheets relative to cleaning and painting ..................................... 8

4.10 Designation of material, tension zones and welds for Fracture Critical Members(FCM’s), including applicable nondestructive testing....................................................... 8

4.11 Material and material testing ............................................................................................. 8

4.12 Incorporation of all necessary revisions into the Shop Detail Drawings........................... 8

4.13 Erection Framing Plan details............................................................................................ 9

ii Copyright © 2000 by the AASHTO/NSBA Steel Bridge Collaboration.All rights reserved.


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4.14 Answer or acknowledge all appropriate questions noted on Shop Detail Drawings

as “Engineer verify” (does not include “Contractor verify” or “Field verify”

queries that must be resolved by others before final Shop Detail Drawingapproval) ............................................................................................................................ 9

4.15 Compliance with Owner-specific or project-specific requirements that may

supersede the requirements of this checklist ..................................................................... 94.16 Special needs for special structures, for example: special handling instructions or

temporary fixtures for lifting, positioning and transportation; protection of

critical components and connections; and dimensional controls required for shopand field assembly. “Special structures” include truss, cable stayed, suspension,

tied arch and moveable (lift, swing, bascule) bridges. ...................................................... 9

Section 5: Return and Distribution of Drawings........................................................................... 10

5.1 Acceptance Levels ........................................................................................................... 105.2 Approval Stamp............................................................................................................... 10

Commentary.................................................................................................................................. 11

Copyright © 2000 by the AASHTO/NSBA Steel Bridge Collaboration.All rights reserved. iii


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Section 1Definitions

Terms used in this document are in accordance with the AASHTO/NSBA Steel Bridge

Collaboration standards. Terms that are specifically significant to this document are defined

below.

1.1 ContractThe “Contract” includes the design plans, the Owner’s standard specifications,

supplemental specifications and special provisions, as well as material specifications and

associated industry standards referenced by the Contract, such as AASHTO, AWS, and

ASTM. The Contract is a binding agreement between the Owner and the Contractor, andany changes must be acknowledged and accepted by both parties.

1.2 Shop Detail Drawings“Shop Detail Drawings” are produced by the Fabricator (or the Fabricator’s representative)

and define how material is to be prepared, assembled, finished, and /or erected. Shopdrawings and erection drawings are types of Shop Detail Drawings. Shop Detail Drawings

typically also include general notes.

1.3 FabricatorThis document addresses the review of drawings that define and detail fabrication procedures, materials, dimensions, tolerances and testing. In this document, “Fabricator”

refers to the facility(ies) performing such shop activities as cutting, welding, drilling,

punching, cleaning and painting of structural steel. “Fabricator” also includes any agents ofthe Fabricator, such as those who prepare Shop Detail Drawings. In some cases the

Fabricator may also be the Contractor, but usually, the Fabricator subcontracts to the

Contractor.

1.4 Owner

In this document, “Owner” refers to the entity paying the Contractor to fulfill the terms ofthe Contract. The Owner encompasses the following: those preparing the Contract

documents, including the “Designer” responsible for the structure’s adequate design; thosewith the authority to review and approve the Shop Detail Drawings, herein referred to as

the “Approver”; and those representing the Owner during construction, commonly called

the “Engineer”. The Designer, Approver and Engineer may be employees of either theOwner or professional firms contracted for the work

1.5 ContractorThe Contractor is responsible for proper completion of all tasks required by the Contract.

Subcontractors, including fabricators, erectors, and field painters may be utilized by theContractor, but the Contractor retains responsibility for all material, operations and the

final product. The Contractor may permit direct subcontractor interaction with the Owner

to expedite the project, but subcontractors must inform the Contractor of any proposed

modifications to Contract requirements accepted by the Owner. The Contractor may permitor reject the changes.

1.6 ApprovalThe Owner’s approval of the Fabricator’s Shop Detail Drawings is a verification that the

drawings appear to be consistent with the Contract documents. “Approval” does not relievethe Fabricator of the responsibility for the accuracy of dimensions on Shop Detail

Copyright © 2000 by the AASHTO/NSBA Steel Bridge Collaboration.All rights reserved.


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Drawings or for complete submittals satisfying applicable Contract requirements, nor does

it permit deviations from the Contract without the Owner’s documented consent.

1.7 Principal Controlling Dimensions, Material and Connection PropertiesThe following principal controlling dimensions, material and connection properties areessential items for reviewing all Shop Detail Drawings:

• Length of span, i.e. the horizontal distance between bearings, pin centerlines or other points of support

• Thickness and width of plates in primary members and splices

• Primary dimensions and/or weight per foot of rolled shapes

• Diameter, specification and grade of mechanical fasteners (bolts, nuts, studs, couplers,etc.) and coating if required (mechanical or hot dip galvanizing)

• All dimensions of machined pins, hangers and complex bearings

• Specification, grade and toughness testing requirements for steel components

• Elevation of seats and other supports for steel members

• Size of fillet and partial joint penetration welds; appropriate partial and complete joint penetration weld configurations

1.8 Construction ChangeModifications to Contract requirements, including design plans, specifications, and special

provisions, after award to the Contractor shall be considered "Construction Changes".These may reflect alterations due to unanticipated site conditions, design plan errors,

changes in project scope, Contractor related problems or Owner initiated changes.

Corrections for Contractor related problems must be proposed in writing by the Contractorwith all necessary details, calculations, material alterations, and/or other pertinent

information for the Engineer's review and approval.



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Section 2Responsibilities

2.1 Fabricator2.1.1 The Contractor and Fabricator are responsible for providing Shop Detail Drawings

that accurately show the appropriate details, dimensions, material requirements andother requirements necessary to fabricate and erect components of the structure inconformance with the Contract documents.

2.1.2 If errors or discrepancies are discovered in the Contract documents, they must be brought to the Owner’s attention.

2.1.3 The Fabricator must obtain the approval of the Contractor and the Owner beforemaking any modifications to Contract requirements.

2.1.4 The Fabricator must ensure all material, geometry, and connections shown on theShop Detail Drawings concur with the Contract, subject to the accuracy of theessential dimensions shown on the Contract documents and any required field-

verified information supplied by the Contractor. The Contractor is responsible for

the fit of the structure in the field.2.2 Owner

2.2.1 It is the Owner’s responsibility to review the Shop Detail Drawings to ensure that theFabricator has correctly interpreted the intent of the Contract documents and that

details properly reflect material and connection requirements.2.2.2 Drawings will be returned with the Owner’s stamp and/or signature indicating either

approval, some type of conditional approval, or rejection.

2.2.3 Rejection, requiring Shop Detail Drawings to be revised and resubmitted, shouldonly be used when drawings either deviate significantly from Contract requirements

without the Engineer’s prior approval, or are unacceptable due to incompleteness,

legibility, or number of errors (see 5.1 on page 10).

2.2.4 The time required to review Shop Detail Drawings must be kept to a minimum toenable the Fabricator to schedule fabrication and complete production in a timely

manner. Subject to Contract requirements, and unless otherwise agreed between the

Owner and Fabricator, drawings for most structures should be returned within 3 to 4weeks, though very complex structures can take longer. Partial submittals that

include all inter-related drawings should be allowed if this is compatible with the

situation and will expedite the project.2.2.5 Construction Changes to the Contract are normally conveyed to the Contractor, but

if changes will affect fabricated items, the Fabricator should also be notified

concurrently.

2.3 Team EffortThe Contractor, Fabricator and the Owner are responsible for approaching the Shop Detail

Drawing submittal, review, approval, and distribution process as a team effort in order to

ensure accurate and timely construction of the structure.

2.3.1 All parties must cooperate and maintain open lines of communication so problemscan be quickly addressed and resolved.

2.3.2 Verbal discussions and agreements are encouraged and should be quickly followed by written confirmation.



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2.3.3 Efforts should be made to expedite information and drawing transmission, includinguse of e-mail, faxes and electronic file transfer when applicable.

2.3.4 Requests for Information (RFI’s) should indicate the urgency of a reply. The Ownershould provide a timely response or acknowledgement (explanation, decision,

request for additional information, or estimate of time needed to evaluate), usually

within two business days.2.3.5 The Owner should be receptive to considering alternate fabrication methods orconfigurations proposed by the Fabricator that will result in improving or equaling

the expected performance, maintenance and longevity of the structure. TheContractor’s acceptance of any modifications that alter the finished product must be

verified before submission to the Owner.

2.4 Professional SealGenerally, Shop Detail Drawings do not require the stamp and signature of a registeredProfessional Engineer (PE). However, there are some circumstances where a PE stamp or

seal is warranted. Contract requirements may also mandate this evidence of a PE’s review.

2.4.1 Shop Detail Drawings may require a PE seal if the Fabricator has proposedsignificant changes to the design of the structure. All changes to the design of thestructure proposed by the Fabricator require the Owner’s and Contractor’s approval,

but not all changes need to be sealed by a PE. Standard practice is for the Owner to

approve or reject changes proposed by the Fabricator, based on the anticipated

effects on the structure and the Fabricator’s justification for the alteration(constructability, reducing distortion or residual stresses, etc.). Fabricator proposed

changes may require a PE seal when they significantly affect structural behavior,

construction or performance.2.4.2 Value-engineering proposals require a PE’s seal and signature, and a formal

submittal from the Contractor to the Owner with all calculations and justifications

for the change.



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Section 3General Review Guidelines

3.1 MaterialsThe Owner will verify that structural materials conform to the contract documents, unless

specific substitutions are approved.3.1.1 Exceptions are permitted when the Fabricator has received prior documented

approval from the Owner for substitutions of equivalent material type, platethickness or member size to facilitate purchasing or fabrication. Such substitution

should be allowed providing there is no additional cost to the Owner and changes

will equal or exceed the Contract requirements. (see 2.3.5)3.1.2 The Owner should permit equivalent substitutions for material less than 10 mm

(3/8”) thick that is not available in the specified material. Alternate structural quality

materials such as ASTM A606 or A570, with corrosion resistance equal to adjacent

material, should be permitted for shims and fills. Substituted material must satisfyspecific required properties (yield, elongation, Charpy V-Notch (CVN) toughness).

3.1.3 Fills and shims do not usually require CVN testing.

3.2 Weld Symbols3.2.1 Weld symbols on Shop Detail Drawings should be compatible with joints shown on

the plans, but for groove welds the Fabricator may prefer joint preparations different

than those indicated on the plans. Alternate weld details should be allowed as long as

the weld satisfies the intent of the plans, does not violate fatigue constraints, and isin conformance with Contract documents.

3.2.2 Fabricators sometimes place Welding Procedure Specification (WPS) identificationnumbers in the weld symbol tail, indicating the procedure to be used. The WPS must be submitted for the Owner’s approval, but for efficiency, this is usually done

separately from the Shop Detail Drawing review and approval process. Therefore,the Approver does not usually review the weld identification numbers shown.During fabrication, the Owner’s QA Inspector will ensure that appropriate WPSs,

approved by the Owner, are used.

3.3 FormatFabricators have different systems for detail drawing presentation, such as drawing orderand designations, piece marking, location of dimensions and wording of notes governing

shop procedures. The Owner should not review or mandate the format.

3.4 Submittal ProceduresShop Detail Drawings should be submitted and returned by the most expeditious routingconsistent with the Contract documents. The Owner should work with the Fabricator, the

Contractor, and other related parties to establish the most effective procedures. Subject to

concurrence by the Contractor and Owner, submission of review copies from the Fabricator

directly to the Approver is optimal. If electronic files are acceptable, the Owner shoulddefine the routing, format and authentication method.

3.5 Number of Drawing CopiesThe Contract documents should indicate the number of drawing copies needed for each

step in the review, approval, and distribution process, and whether any reproducibles must be supplied to the Owner or other parties.



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3.6 Reduced-Size CopiesTo simplify handling, the use of reduced-size (11” x 17”) copies may be permitted by the

Owner for review and/or distribution. Clarity and legibility of details, notes and materiallists must be maintained with any format utilized to avoid errors and provide a permanent

record for future maintenance and structural evaluation. Adequate space must be provided

for approval stamps on each drawing.3.7 Accuracy

Steel fabrication details are normally shown to the nearest 1 mm (1/16”), but if details vary

from plan dimensions by small amounts, the details should be approved unless a significant

cumulative error results. Machined surfaces are an exception to this tolerance.

3.8 Drawings Not RequiredDepending upon the Owner, some minor fabricated items, such as drains, pedestrian

fencing and armor bars for compressible seal joints, may not require submittal of Shop

Detail Drawings for review. The Fabricator should research the Contract documents orcontact the Owner to determine any such policy and save preparation and review time.



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Section 4Approval Checklist

The following is a list of common items that should typically be checked on Shop Detail

Drawings. Unusual designs may contain unique details that are beyond the scope of this guide

and not fully covered here. The reviewer’s judgment must prevail in determining the extent and

depth of review on each project.

4.1 Principal Controlling Dimensions, Material and Connection PropertiesThe following principal controlling dimensions, material and connection properties shall be

considered essential items for reviewing all Shop Detail Drawings:

• Length of span, ie. the horizontal distance between bearings, pin centerlines or other points of support.

• Thickness and width of plates in primary members and splices.

• Primary dimensions and/or weight per foot of rolled shapes.

• Diameter, specification and grade of mechanical fasteners (bolts, nuts, studs, couplers,etc.), and coating if required (mechanical or hot dip galvanizing).

• All dimensions of machined pins, hangers and complex bearings.

• Specification, grade and toughness testing requirements for steel components.

• Elevation of seats or other supports for steel members.

• Size of fillet welds and partial joint penetration welds; appropriate partial and complete joint penetration weld configurations

Note: 4.1 repeats 1.7 due to the importance of the items listed and their applicability to all

subsequent subsections.

4.2 Web and flange plates of welded members and rolled beam stringers

• Shop butt weld splice locations

•

Flange and web tapers and haunches (controlling dimensions only)• Cover plate dimensions and termination details.

• Location of tension and compression zones in welded members

4.3 Stiffener and connection plates

• Width, thickness, material grade and if toughness testing required (curved bridge, floor beam connection, etc.)

• Weld size and termination details and bolting to web and flange details

• Appropriate spacing of intermediate stiffeners

• Avoiding interference with shop web and flange splice locations

• Fit and location of stiffeners

• Bolt hole edge distances and compatibility with diaphragm/cross frame connections.

4.4 Bolted Splices

• Length of flange splices, width and depth of web splices

• Number, size and spacing of bolts and holes in splice material

• Fill plates if necessary

• Proper bolt hole edge distances

4.5 Crossframes and diaphragms

• Number and spacing of connection plate bolts, and type of holes, especially for slipcritical connections or details required for differential deflections.



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• Length termination details and number of shop welds

4.6 Camber and/or mid-ordinate for cambered rolled beams or girder sections (spotcheck)

4.7 Elevation at center of span or segment, field-splice, abutment and pier ordinates on

shop assembly diagrams4.8 Number and spacing of bolts in floor beam and cross girder connections as well as

special attachments (brackets, pot bearings, etc.)

4.9 General notes and detail sheets relative to cleaning and painting

• Corner preparation (if required for cut edges)

• Cleaning, required surface preparation (SP6, SP10, etc.) and profile depth (if specified)

• Shop Primer: type; manufacturer; wet or dry film thickness; verification of cure beforeshop application of subsequent coats (required); applicable restrictions on field contact

(faying) surfaces; any requirements for pre-priming shop contact surfaces before

assembly (e.g. inside boxes, shop bolted assemblies); and designation of any field weld

areas to be left unprimed• Top Coat(s): shop or field; type; manufacturer; wet or dry film thickness; intermediate

coat cure times and/or recoating “window” (time) if specified by the Contract documents

or paint manufacturer’s data sheet; any blockout areas where shop topcoats are not permitted (e.g. field splices, diaphragm/cross frame connections, bearings)

4.10 Designation of material, tension zones and welds for Fracture Critical Members(FCM’s), including applicable nondestructive testing

4.11 Material and material testing

• Material specified in accordance with the Contract documents

• Substitutions for material less than 10 mm (3/8") thick , especially fills and shims (see

3.1)• Substitutions for material over 10 mm (3/8") (see 3.1)

4.12 Incorporation of all necessary revisions into the Shop Detail Drawings

• Errors or discrepancies in the Contract plans discovered during Shop Detail Drawing preparation or review

Such errors must be conveyed to the Owner and the Contractor to determine andimplement appropriate corrective actions. Depending on the extent and importance,

Contract plan corrections or project modifications may be distributed by the Owner as

Construction Changes or notification may be verbal, followed by writtendocumentation to all parties.

• All Construction Changes that affect the Shop Detail Drawings

Recent Construction Changes not incorporated into the Shop Detail Drawings do notusually justify rejection. Unless changes will drastically alter fabrication details, a copyof the Construction Change may be returned with “approved as corrected” Shop Detail

Drawings in such circumstances. Note: Corrections noted on Shop Detail Drawings do

not constitute “Construction Changes” and should not be used to informally effectConstruction Changes.

• Fabricator-proposed modifications approved by the Owner and Contractor



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These include deviations from the Contract requirements, substitutions of material or

modifications to the Contract plan details, based upon the Fabricator’s request (at no

cost to the Owner), that have received prior approval from the Owner and Contractor.

4.13 Erection Framing Plan details

• Basic span lengths and, where appropriate, transverse girder spacing

• Pier and abutment identifications• Orientation of structure (north arrow), skew(s), spot checks of curve or flare geometry if

applicable

• Adjustments for special bearings, expansion joints or other items not adequately covered by the contract plans to compensate for temperature or other variables where applicable

• Piecemarks indicated for every element, and their relative location (end, side) is shown toclarify member orientation

4.14 Answer or acknowledge all appropriate questions noted on Shop Detail Drawings as“Engineer verify” (does not include “Contractor verify” or “Field verify” queries that

must be resolved by others before final Shop Detail Drawing approval)

4.15 Compliance with Owner-specific or project-specific requirements that may supersedethe requirements of this checklist

• Inclusion of Owner requirements for sheet title box information (contract number, bridgeidentification number , pay item, etc.)

• That standard title box notes (hole diameter, welding, paint, etc.) do not conflict withContract requirements

• Proper notation of revision date(s) and number(s) on revisions after the first submission

• Miscellaneous project-specific items such as utility attachments, special connections orconnection materials (pins, links, cables), and stage removal and construction

• Professional Engineer Seal if required.

4.16 Special needs for special structures, for example: special handling instructions ortemporary fixtures for lifting, positioning and transportation; protection of critical

components and connections; and dimensional controls required for shop and field

assembly. “Special structures” include truss, cable stayed, suspension, tied arch and

moveable (lift, swing, bascule) bridges.



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Section 5 Return and Distribution of Drawings

5.1 Acceptance Levels5.1.1 Acceptable Shop Detail Drawings should be “Approved” and expeditiously returned

to the fabricator.5.1.2 The Shop Detail Drawings should be conditionally accepted (“Approved as Noted”,

“Approved as Corrected”, “Accepted Subject to Comments”, etc.) if required

corrections are limited and the Owner is satisfied that the drawings fundamentally

satisfy the Contract. Examples of limited corrections include sporadic, minordimensional errors and shop notes not fully consistent with specifications or special

provisions. Conditional approval permits the Fabricator to proceed with limited

fabrication (subject to availability of QA inspection or other Owner restrictions).Shop Detail Drawings must be corrected and copies returned to the Owner and full

approval obtained before unrestricted fabrication begins.

5.1.3 Drawings should not be returned stamped “ Rejected” or “Revise and Resubmit”

unless the drawings cannot be “Approved” or “Approved as Corrected” due tononconformance, poor quality (legibility, lack of adequate dimensions, details and/or

notes, contradictory information, etc.) or other problems that may lead to significant

shop errors. Only individual sheets with such errors or required modifications should be rejected. Other sheets may still be fully or conditionally accepted unless their

required interaction with the rejected drawings precludes this possibility.

5.2 Approval Stamp5.2.1 The Owner will stamp each drawing to indicate acceptance. The stamp indicates the

Owner is satisfied that the Shop Detail Drawings generally conform to the intent and

requirements of the contract documents, but the Fabricator and Contractor remain

responsible for satisfying all Contract requirements.

5.2.2 If the Approver is a contractual agent of the Owner rather than an employee of theOwner, the stamped plans may be sent to the Owner if required for further

acceptance and processing. If the structure will carry a railroad, rapid transit or otherloads besides the Owner’s, then “Approved” copies may be routed to such

organizations for their concurrence and/or approval.



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Commentary

C2 Owners (or their agents) review Shop Detail Drawings to “ensure that the Fabricator has

correctly Interpreted the intent of the Contract documents and that details properly reflect

material and connection requirements” (2.2.1). Regardless of the Owner’s review and approval,

the Contractor and the Fabricator are responsible for the accuracy of Shop Detail Drawings(2.2.1), the “Fabricator must ensure all material, geometry, and connections shown on the Shop

Detail Drawings concur with the Contract” (2.1.4), and the “Contractor is responsible for the fitof the structure in the field” (2.1.4).

C2.3.5 Some examples of alternative methods or configurations that may be proposed include:

• use of weld joint configurations providing equivalent strength and fatigue resistance (seeC4.1)

• increase of the thickness of connection plates or intermediate and longitudinal stiffeners toavoid welding problems

• relocation of flange and web butt welds or field splices slightly to miss adjacent

• details or facilitate use of plate lengths available from mills

• avoiding beveled plates by angling other connections

• reducing residual stresses and possible plate damage by avoiding highly restrained welds

• alteration of a weldment’s configuration to permit access for fabrication

• use of two thinner fills instead on one heavier fill

• substituting either equivalent types of material or thicker material due to availability

The Approver may discuss proposals with the Designer and Fabricator to better understand

the rationale and potential problems or benefits.

C3.4 Subject to concurrence by the Contractor and Owner, review copies are optimally sent

directly to the Approver, avoiding delays associated with re-transmittals through other offices. Ifdesired, the Contractor may concurrently receive “draft” or “for information only” copies, but

care must be taken not to confuse these with later approved versions. At least two copies of all

drawings are sent to the Approver so one set marked with any corrections or comments can bereturned with instructions for subsequent submittals.

C4.1 The Owner should adequately check geometry to verify that the shop details generally

conform to the intent of the design and permit proper assembly. Shop girder laydown diagrams

should be selectively checked to insure the girder profiles are consistent with the plan

configuration, including support locations. Spot checks among similar members may suffice, butif errors are found, more in-depth reviews are needed.

Longitudinal and lateral dimensions in the Contract plans are usually in the horizontal plane, but

Shop Detail Drawings reflect true dimensions along the individual member and account for

changes in slope, grade and camber corrections, so the Approver must consider this in thereview. Small inconsistencies between the Approver’s calculations and detail dimensions for

such items as camber or sweep ordinates should not be noted for correction as fabrication

tolerances in the Contract documents permit such deviations and they will not impedeconstruction or affect performance.

Fillet welds are usually based on the minimum sizes permitted by Section 2 of the current

AASHTO/AWS D1.5 Bridge Welding Code (BWC). The minimum required fillets are 6 mm

(1/4") for material up to 20 mm (3/4") thick and 8 mm (5/16") for heavier plates, minimizingresidual stress and distortion, especially on thin material. In areas of high shear or when two



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plates must act together, larger fillet welds may be needed, and these should be specified on the

plans. Flange to web welds begin and end beyond the limits of the completed member, so they

are continuous, but stiffeners and connection plates have fillet welds terminating on webs andflanges. These welds should end about 6 mm (1/4”) away from an edge (snipe, clip, etc.) to avoid

a poor quality weld termination. Many configurations will provide complete joint penetration

(CJP) and partial joint penetration (PJP) welds, and the Fabricator should be allowed reasonablelatitude in selecting a joint. Preferred joint configurations are shown in Figures 2.4 and 2.5 of the

BWC. If the plans necessitate a joint not prequalified by the BWC (e.g.: a fillet or CJP weld

between two converging plates with a 25 degree included angle), alternates proposed by theFabricator should be considered. (See C2.3.5)

C4.2 Some owners may also require: tension zones to be identified on flanges to clarify welding

and NDE requirements; verification of minimum and maximum lengths between welded splices;

or approval for butt welds not shown on the design plans. Unless otherwise stipulated, plategirder flange and web butt welds as well as nearby stiffener or connection plate attachment welds

should be separated by at least 150 mm (6") to avoid adverse interaction of intersecting weld

zones.

C4.3 Bearing stiffeners typically stipulate “mill to bear” at the flange attached to the bearing toinsure direct, steel-to-steel load transfer. This may also be achieved by a “grind to bear” or

“finish to bear”, especially where stiffeners are not perpendicular to flanges. The opposite end of

the bearing stiffener is normally “tight fit”, thereby forcing the bearing end into intimate contact.

The Bridge Welding Code establishes requirements for these fits, so they need not be furtherdefined on the drawings. Intermediate stiffeners, connection plates and girder webs (even over

bearings) do not require “mill to bear” or “tight fit”. AASHTO requires bearing stiffeners

supporting diaphragms or cross frames to be attached to the flanges, but this does not eliminatethe requirement for a bearing fit at the supporting flange.

C4.4 Computer numerically controlled (CNC) equipment may be used in lieu of drilling,

subpunching and/or reaming. The Approver should contact the Owner if the Fabricator proposesa method not specifically allowed by the Contract documents. When the Contract plans specifyedge distances, the Fabricator may increase them (including at the girder ends) slightly, as long

as splice plates neither encroach fillet welds nor interfere with adjacent material. This may avoid

problems if a drill or plate is not exactly positioned. Since owners require rotational capacity(RC) testing of high strength bolt assemblies immediately before installation in the shop or field,

bolt lists should reflect adequate additional bolts for testing, loss, etc. For slip-critical

connections, bolt holes may be drilled or reamed in assembly to insure accuracy, but this may not

always be possible or practical. CNC equipment, templates with hardened steel bushings, fielddrilling or reaming and other methods may be used in lieu of assembly if permitted by the

Contract documents and accuracy and quality (holes not elongated) can be assured. This may

include a limited number of check assemblies or comparative templates.C4.5 Depending on the structure’s cross section and the plan details, the Fabricator may haveconsiderable latitude in detailing cross frames. The Approver should only verify that the

proposed geometry and joining methods will satisfy the intent of the design. Unless critical to the

assembly’s structural performance, such items as the exact length and orientation of cross framecomponents, shapes of gusset plates, and whether rows of bolts are parallel to the girder web or

the edge of the gusset may be left to the Fabricator’s preference. If the plans stipulate slotted

holes or other provisions to accommodate differential movement or to limit rotation of adjacentgirders, the bracing must incorporate these considerations. Provisions to control differential



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deflection or lateral movement (twist) during construction should be addressed on the Contract

plans or agreed to between the Owner and Contractor.

C4.9 Unless superceded by Contract document requirements, surface preparation and coating

application should be governed by the manufacturer’s product data sheet instructions. All coatsin a system (primer, intermediate and top) should come from the same manufacturer to insure

compatibility and accountability. The shop coat manufacturer should be shown on the ShopDetail Drawings to insure the field coat(s) comply.

C5.1.2 If the Shop Detail Drawings appear to have misinterpreted the Contract plan requirementsor if the Approver is uncertain regarding detailing methods (eg. camber presentation or cutting

diagrams), the Approver should contact the detailer directly to avoid unnecessary markups or re-

submittals. When errors are extensive, the review should be terminated and the drawingsreturned. The Approver may include recommendations to facilitate corrections of minor or

occasional errors, but extensive corrections should not be provided. The Contractor/Fabricator

remain responsible for drawing accuracy, even if suggested corrections are provided.

shop detail drawing review and approval guidelines

Documents